Centrifugal separators are widely used as a means to separate solids from flowing streams of water in which they are entrained. The classical arrangement is to inject the stream from a nozzle tangentially into a cylindrical separation barrel. As the stream whirls around the wall of the separation barrel, the high g forces within the stream cause the solid particles to migrate toward the wall as the whirling stream flows from an upper elevation to a lower elevation in the separation barrel. At or near a lower end of the separation barrel there is a spin plate which reflects the central portion of the tubularly shaped whirling stream upwardly toward a central exit port. This central portion of the stream is substantially free from solids in a properly designed and properly operated centrifugal separator.
There is a slot near the spin plate either through or at the lower end of the separation barrel through which the solids that are nearer the wall of the separator barrel will pass. These solids formed part of the outer portion of the stream which is contiguous to the wall.
This type of centrifugal separator is shown in Laval Jr. U.S. Pat. No. 4,072,481 which is incorporated herein by reference in its entirety for its showing of the theory and practice of such separators.
Devices of this type are frequently used to separate solid particles over a large range of sizes. Apparatus using this principle extend in sizes from as small as parts cleaners for use in automobile service bays, through large factory installations for separating crop washings and floor sweepings from wash water, to removal of grit from very large water distribution and irrigation systems.
This is a passive system whose function and efficiency are in large part derived from the velocity and smoothness of flow of the stream in the separator. Turbulence anywhere in the system, or inefficiency in the introduction of the stream into the separation barrel, will result in the need for more power (higher injection pressure), or a reduction in efficiency of separation.
A further problem arises from the abrasive nature of the solids themselves. In order to generate the substantial g forces, required, the velocity of the particles and the force of their contact with parts of the separator will result in a substantial wear rate that can only partially be compensated for by the use of steel alloys. This is especially the situation at the edges of slots through which the solids-laden water passes from an acceptance chamber when it enters the separation chamber. Non-turbulent smooth flow results in reduced wear throughout the entire system.
It follows that reduction of turbulence, and disciplining of the stream can importantly improve separation, reduce power cost, extend the time between repairs, and extend the useful life of the device. It is an object of this invention to provide such improvements.